This research program is concerned with the etiology, pathogenesis, prevention, early detection and treatment of the Respiratory Distress Syndrome of infancy. We propose to develop predictive indices with the aid of a computer to identify the fetus or infant at highest risk of developing hyaline membrane disease, and in particular, those infants who are likely to die or require prolonged and complicated therapy. New methods of monitoring the fetus are being explored viz fetal breathing and continuous recording of PO2 by transcutaneous techniques. The biochemical development of the lung, the distribution of water in the lung as well as the influence of vasoactive polypeptides are being studied and the influence of asphyxial insults on these determined. The intracellular pH during acute hypercapnea is being studied experimentally to determine the in-vivo buffering capacity. New means of controlling serious bacterial infection through the implantation of normal bacterial flora as a host defense mechanism is being explored and a detailed metabolic evaluation of various nutritional regimens currently in use or proposed for the near future is being undertaken. Summary of supplemental application: To define the inter-relationship of the kallekrein-kenin, renin-angiotensin and catecholamine systems in the modulation of circulation responses to premature birth and perinatal stress. To study the oxygen uptake and delivery in RDS during use of continuous distending pressure and as a result of exchange transfusion.